Pressac was originally a Holocaust denier who, with Robert Faurisson, attempted to disprove what he considered historically inaccurate depictions of the concentration camps as extermination camps.
However, upon visiting Auschwitz in 1979 in 1980, Pressac was able to
view first-hand the extensive archive of original German documents
thanks to the courtesy of the museum staff and administration unaware of
the true purpose of his research. In Poland, Holocaust denial is punishable by law.